The first large-scale power storage facility in the United States will use British regenerative fuel cell technology to store electricity.HOUSTON, Texas, US, 2001-11-14 [SolarAccess.com] The US$25 million plant will be built by the Tennessee Valley Authority on a two-acre site near an Air Force base at Columbus, and is expected to take up to two years to complete, creating 60 jobs before the project is finished in 2003. “This innovative energy-storage plant is designed to improve power reliability and customer service, have limited environmental impact and contribute to economic growth for consumers in Mississippi and throughout the Tennessee Valley,” says TVA chairman Glenn McCullough. “TVA continues to set the pace for energy production and demonstrate its role as a national leader in the use of cutting-edge, 21st century technologies.” The plant was designed by Regenesys Technologies, part of Innogy plc (UK), to use regenerative fuel cell technology. During periods of low electrical demand, the fuel cells are charged with electricity generated at other locations, and released during times of demand. The facility is designed to store up to 120 megawatt-hours of energy and will be capable of providing power to 7,500 homes for up to ten hours. The regenerative fuel cell technology provides a reversible electrochemical reaction between two salt solution electrolytes, sodium bromide and sodium polysulfide. The electrolytes are close together in the battery cells, and separated by a polymer membrane that allows only positive sodium ions to pass, producing 1.5 volts. Cells are electrically connected in series and parallel to obtain the desired voltage and current levels. The net efficiency of this battery is 75 percent, and has been verified in the laboratory and demonstrated in Britain.